In recent years, what is known as a four-sided secured soft tension mask has been proposed as a film-forming mask composed of a mask body having a pattern of openings that admit film formation material to pass, and a holding frame for holding the mask body, as disclosed in, e.g., Patent Document 1. The four sides of the mask body 41 are enclosed by the frame 42, and the mask body 41 is held in place while very light tension or no tension is applied by the frame 42 from four sides, as shown in FIG. 1.
The four-sided secured soft tension mask is advantageous in being lightweight and having little temperature variation. Since temperature variation is low, pattern displacement is not liable to occur during deposition performed by a vapor deposition device, and the lightness of weight enables transportation-related costs to be reduced.
[Patent Document 1] Japanese Laid-open Patent Application No. 2007-138256